The events could have been taken from a Bollywood potboiler. Last week fears were raised that somebody had tried to murder Anil Ambani — the Indian telecoms tycoon who is one of the world's richest men — by sabotaging his private helicopter.

Yesterday police were investigating after the technician who reported the suspected sabotage was found dead on a Mumbai railway track.

Bharat Borge, 47, an engineer for a private maintenance company, noticed on Thursday last week that the fuel cap of the Bell 412 helicopter in which Mr Ambani was due to fly the next morning had not been replaced properly. He then discovered gravel in the fuel tank.